FIG. 4 shows a principle of arrangement of a known hybrid power train of a vehicle. A combustion engine 10 is connected through a friction clutch 12 to an electric machine 14 that is operable as a motor and as a generator, which in turn is connected through a torque converter 16 that operates for example hydraulically, to an automatic transmission 18, which drives driven wheels 20 of the vehicle. Depending on its operating state, electric machine 14 works together with an energy storage element 22, which is charged when electric machine 14 is in generating mode and from which energy is taken when electric machine 14 is in motor mode.
Friction clutch 12 is actuated by a clutch actuator 24, for example an electric motor.
The power train example just described is controlled by an electronic control device 26, with inputs 28 that are connected to sensors for detecting the operating state of the power train, for example an accelerator pedal sensor, a transmission selector lever sensor, a speed sensor for detecting the speed of rotation of combustion engine 10, a load sensor for detecting the setting of a load control element of combustion engine 10, a sensor for detecting the speed of rotation of a vehicle wheel, etc. Outputs 30 of electronic control device 26 are connected to actuators and other control devices to control the operation of the combustion engine, the electric machine 14, the automatic transmission 18 as well as possibly the converter 16. Only the connection of an output of electronic control device 26 to clutch actuator 24 is shown.
Electronic control device 26 contains a microprocessor with corresponding program and data memories, so that the respective actuators and setting elements are controlled according to predetermined programs, depending on the input signals. The construction and function of the power train, which can be modified in many ways (for example, the converter 16 can be omitted) are known, and therefore will not be explained.